Many electronic devices perform their operations using timing of one or more clock signals generated by one or more clock generators included in the devices. Phase locked loop (PLL) clock generators are widely used to generate clock signals. A conventional PLL clock generator traditionally may have a long frequency transition time, e.g., when the PLL clock generator switches from one frequency to another. During such a frequency transition, the frequency behavior of the clock signal generated by the PLL clock generator may be unpredictable. Thus, it may not be possible to rapidly change frequency of a clock signal generated by the PLL clock generator.